


How to Shield the Heart

by roxyryoko



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Canonical Character Death, Emotional Hurt, Emotional Hurt/Comfort, F/M, Family Death, Fire Emblem: Three Houses Blue Lions Route Spoilers, Other Ships Not Mentioned in Tags
Language: English
Status: In-Progress
Published: 2020-01-01
Updated: 2020-01-01
Packaged: 2021-02-27 10:01:53
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 4,596
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22065193
Author URL: https://archiveofourown.org/users/roxyryoko/pseuds/roxyryoko
Summary: Sylvain Jose Gautier broke hearts with ease. With slithering lies and misrouted vengeance.However, now he had one heart he promised he would do anything to protect. After the siege of Fort Merceus, Mercedes is shattered with guilt and sorrow over Emile's death.Breaking hearts was easy, but mending them took more than an insincere smile and flowery words.
Relationships: Sylvain Jose Gautier/Mercedes von Martritz
Comments: 12
Kudos: 43





	How to Shield the Heart

**Author's Note:**

  * For [Nenalata](https://archiveofourown.org/users/Nenalata/gifts).



> Hello everyone! I've been working on this story slowly since I beat my first route! I hope you all will enjoy it! Thank you very much Nenalata for inspiring me to write again. It's been so wonderful and meaningful to get to know you.

Sylvain Jose Gautier broke hearts with ease. With slithering lies and misrouted vengeance.

_“You think I'd cheat? On you, baby? Never.”_

_“It was just a little tryst. Don’t be like that. I hate seeing a girl cry, especially one as beautiful as you.”_

_“This was fun, but you just aren’t the one for me, babe. I’m sure you’ll find another noble with a crest. Heck, I’ll even introduce you to some.”_

They should know not to so easily entrust something so precious, so defenseless to this good-for-nothing, but pretty words and the prospect of crest-infested children easily and always ensnared them.

Yet there was one heart he didn’t want to break.

_“I’m serious. You’re special Mercedes. I’ll give you whatever you want. You want my loyalty? Commitment? Done. I won't so much as look at another woman.”_

_“While I do appreciate the...sentiment, if you really are serious about courting me, I suppose what I really want is for you to always be sincere.”_

_“Bad habits are hard to break, you know? But, for you, I promise I’ll try my best to be more honest..._ and _I promise to win you over.”_

* * *

The sky rumbled as the raging tempest ceaselessly assaulted the massive stonewalls of Fort Merceus. High upon its highest tower a blue flag whipped violently, thundering claps echoing its motion, as if the lion motif emblazoned upon it was roaring its victory. The Goddess’ tears soaked the grounds, continuously mixing the blood of foe and friend. The billowing flames of war had been extinguished hours ago, but the scars the Stubborn Old General sustained would be a scarlet letter when daylight broke.

The inner ward was solemn and abandoned, the citizens still locked inside as precaution. The only sign of life was the rhythmic march of Kingdom archers upon the upper walls. 

Inside the fort a forlorn hum of moans and sniffles punctured the air as Manuela instructed monks and volunteers on the care of the overwhelming victims of battle. Both Kingdom soldiers and the remnants of the Imperial army were to be treated equally by her command. She weaved wearily through the overcrowded soldier’s quarters, trying her best to provide comfort and relief to as many as she and her team could. However, it almost seemed like an impossible task.

The bunks were filled to capacity and many more injured lay wrapped in bandages upon salvaged blankets set up along the perimeter of the repurposed room. The fight to live was still raging for many, and many more lay motionless in defeat. Quickly, another would replace them as the gravely injured filtered in ceaselessly.

Sylvain’s head spun as his eyes roamed lethargically around the large stone room. Everything was out of focus and overpoweringly bright. The little he could make out was unfamiliar and if he was more conscious he’d hate to admit it slightly frightened him. He tried to sit up, but an acute pain ripped through his lower back to his left leg, and halted any further motion. He gasped sharply and a curse word or two fell out of his lips. A wave of nausea twisted in his stomach and he breathed deeply in and out in an attempt to overcome it.

Suddenly, two hazy Mercedeses appeared overheard. Angelically rim lit from the low glow of candles, the two benevolent faces slowly weaved together, becoming one. She knelt down beside him and her lips pulled up softly, and Sylvain couldn’t help the uneasy feeling that her smile didn’t feel quite right, but his mind couldn’t put together such complicated thoughts at the moment.

“Good morning Sylvain,” she spoke gently. 

He couldn’t form words to answer, and could only manage to blearily stare back.

“Don’t worry. You’re going to be alright.” Soothingly, she gave his hand a gentle squeeze. “Would you like some water?”

Her voice seemed to echo from far away, out of focus and broken. He struggled to comprehend her and only could display his confusion with some incoherent mumble. 

She brought a glass to his lips and the other hand cupped around the nape of his neck, lifting him up carefully to help him drink. He took a few sips, instincts kicking in to fill his parched throat. When he finished, she set him down just as gently, and put the glass back on the ground next to him. 

“I’m sure this is all very confusing.” She tenderly wiped water droplets off his face with the corner of her sleeve, and then brushed his sweat-drenched hair from his eyes. “You poor thing. You must have terrible chills.” Mercedes empathetically shuddered as a cold draft blew across the stone floors.

Maternal as always, she adjusted the thin blanket up to his neck and tucked him in better. Pausing thoughtfully a moment, she untied the woolen shawl around her shoulders and gingerly placed it atop the blanket. “Please try to rest. You hit your head rather hard when you fell off your horse.” 

His mind whirled. Fell off his horse? Did he get too cocky again? Another thing he didn’t have the energy to scrutinize. 

The weight of fatigue tugged at his eyelids and Mercedes’ warm fingers combed tenderly through his hair. He soon gave up the struggle to keep his eyes open. Lulled by the soothing scent of lavender wafting from Mercedes’ scarf, he quickly eased into a haze.

Even a clatter and Raphael’s shouting—“Professor Manuela! He’s hurt real bad! You gotta help ‘im!”—could not break the spell.

Even frantic heels clicking on the stone floor and Manuela’s commanding, “Put him down here!”

Even a feeble, “I tried to stop him, Professor…”

Even someone gagging, “Of course, he wouldn’t lis —ugh—so much blood. I’m going to be sick.”

Even Mercedes’ fingers slipping from his temple and the cot shifting as she hurried to her feet, pleading, “Please, let me help.” 

Despite the following anguished groans and distraught voices, Sylvain soon drifted into sleep. 

Scattered and fuzzy, the last battle returned to him in his nightmares.

* * *

Under the fallen gate of Fort Merceus, the Lance of Ruin skewered through the chest of an Imperial officer. Blood spluttered from the woman’s lips with her last rattled breath, and within a moment she toppled back, life snuffed out, limp and heavy upon the other end of the shaft. Faceless and nameless. Just another tally to the ghosts who already haunted him. Quickly, Sylvain yanked the lance out with a stomach churning crack of snapping bones and a squelch of severed flesh. Under his fingers the bloodied relic hummed, hungry to fulfill its purpose of conquest.

It was just one blink in the chaotic pulse of war.

His eyes snapped to the next enemy—the next ghost—and his body moved on instinct as he severed the threads of life. Another stifled choke; another unfinished utterance; another noise to add to the anguished screams, enraged howls, thunder of hooves, the roar of wyverns, the clang of metal, and the many other dissonant notes in this deranged symphony of battle. There’s no time to think or regret or pity. Only time to die or to live, and despite fighting like he wished to die, he’d rather live. 

Sylvain pumped his relic high over head with a defiant bellow of “Advance!” and spurred his steed forward. A wave of both man and beast echoed a roar and followed him into the unknown dangers of the inner fort, cleaving enemies into disassociated limbs and painting the cobble into canvases of red. 

Man became monster. Soaked in blood and soaked in sin. 

Despite the triumphant fury, there was desperation in the Kingdom assault. A week’s long siege had wearied the soldiers and fatigue tugged at everyone’s bones. It had been a long seven days of fruitless magical bombardment, of arrows that ricocheted off stone more than pierced through flesh, of men and winged beasts that scaled walls only to lose the sky’s freedom forevermore. Six days of catching glances of His Highness and the Professor pacing in a tent, the chess pieces of war laid across an unsteady table and even more unsteady hopes. Five days of rations no one had time to eat and sleep that never came by choice. Two days of placing reluctant faith on the Bergliez defector and a small team to infiltrate his former playground to raise the gate. And less than fifteen minutes ago he proved his allegiance and released the depths of hell on his ex-country men. 

The Adrestrians, although shocked and ill-prepared that these unbreakable walls would ever break, resisted with a savage passion. All around Sylvain his infantry fell. Tangled in struggles of his own he would catch a glimpse of their final moments. Arrows pierced their necks, swords sunk into their backs, horses toppled over riders with an anguished bray. Soldier after soldier struck down and went on ahead to meet the Goddess. He swallowed the guilt each time, and repeated to himself, _this was all for our future_.

A cry for help rang through the cacophony, and he almost doubted that he heard anything in the overpowering noise, but the voice wailed out again— more urgent than before, and this time he recognized its owner. His lance hacked a hole through the last nearby threat and he twisted, yanking the reigns for his horse to follow. He searched across the sea of bodies and the ruthless duels for Marianne. 

She wept a stream of tears and crouched beside that horse that she loved so much. It was laid out on its side, sorel coat sullied in blood and dirt. Her fingers were just as sullied and just as dirty as she soothingly brushed over the wide gash in its breast, white magic knitting the wound closed. Yet her desperation proved the beast was fading faster than her magic could repair.

Sylvain dug his spurs into his own steed’s sides, reciting incantations in his head in hopes that his mediocre magic could somehow help; could somehow stop that smile she only recently mastered from falling forevermore to a frown, when—

He noticed Mercedes—divine as always—climbing off her pure white mare, hand wrapped around the neck of a tall staff. Her lips moved to a chant he couldn't hear and the emblem in the staff gleamed a blinding radiance, catalyzing the magic that gently swept across the battlefield. The healing tide washed far and wide, even reaching Sylvain so many yards away. It was comforting like a mother’s caress, and he felt surprisingly relieved when cuts and scrapes he thought had numbed grew warm and stung no longer. 

The horse stirred and whinnied loudly. A thankful smile brightened Marianne’s visage and Mercedes’ smile was reassuringly gentle in kind. She placed a hand on the other’s shoulder and pointed the staff toward the now nearly closed wound on the stallion. Marianne’s spell joined with hers and—

A soldier nocked an arrow to Sylvain’s right, and his body moved in an instant. The man was already injured, hands shaking to pull back the bowstring, but his aim was locked on the mages, and for that Sylvain had no mercy. He was dead in a breath, before he even knew the cavalier with his monstrous lance towered above him. 

_“I'm here to protect you. Will you protect me in return?_ ” Mercedes’ words echoed in his ears, above the screams; above his own heartbeat.

False promises always slipped easily from Sylvain’s lips. 

But this promise was not made with the same disingenuous smile that hid those lies. _This_ promise was made with sincere tears and a sad smile. Much like the commitment to country and the loyalty to friends that brought him inexplicably to this battlefield, he intended to keep it. Because Mercedes was different than those other girls.

Sylvain pulled on the reigns, grip taunt, and drew his horse around, searching for the next threat. 

And there were too many.

He surged both man and beast into a bloodbath, eyes blazing with wrath, hooves stampeding over the mounting bodies of both ally and enemy. The Lance of Ruin took life after life. Yet he couldn’t calm the gnawing worry that the monk platoon was too close to the butchery. It wasn’t safe yet and he needed to ensure it was to keep his oath. 

Lightning split the ground in front of him and an ear-splitting boom followed in quick succession. His horse reared up in fear, and the cobbled walls of the massive fort shook while debris fell in heavy clouds. Before he could find the spell-caster, the smoke and dust stung his eyes and he impulsively squeezed them shut.

Something —an arrow —whooshed past, threateningly close to his ear, rustling his hair and tickling his skin. He struggled to open his watery eyes, and his heart pounded in his chest under this vulnerability. He barely had opened them a crack when a sharp, hard object smashed into his side. His armor blunted the damage, but not the force and he was propelled sideways. The horse reared up again, and this time his hand slipped from the reigns and his legs slipped from the stirrups.

He tumbled across the dirt until stopped by the cold armor and colder flesh of a fallen soldier. Vibrations of skittish hooves pounded the ground too close for comfort and he rolled away from the dangerous impact. Sylvain cursed, fumbled to his knees, and rubbed his burning eyes. He barely had squinted them open when he heard the plodding of heavy footsteps. He twisted around, thrusting the—

Where was the Lance of Ruin?

He blinked and the enemy soldier was mere steps away, axe brandished high in the air.

He blinked and whirled his head around, locating the pulsating relic to his left, out of reach.

He blinked and the soldier arched the axe down.

Damn it! He lunged to his left in a final effort to scramble away. He couldn’t allow himself to get injured—or worse—when Mercedes was still so close to the chaos.

But a body not a blade crashed into his thighs. And this body had a tomahawk embedded in its newly dead back. 

Grateful for the rescue, Sylvain’s head whipped up. The Bergliez guy stood not far away, hand still stretched out from the throw, drenched nearly head to toe in blood, dirt, and sweat. A manic grin tugged across his lips and his eyes gleamed with satisfaction.

Another arrow zipped above Sylvain’s head, and before he could register it as friend or foe, another body collided with the ground inches from his fingertips, the thud resonating across the stones.

“Are you alright there, Sylvain?” called Ashe. He stepped forward, out of the shadows, already preparing another arrow.

Sylvain pushed the corpse off his legs and swiftly grabbed his relic. Clambering to his feet, he jabbed a finger toward Ashe. “This—,” he declared. “This is what I’m talking about! You’ve seized my heart, Ashe! My valiant hero!”

“Well, judging by your jokes, I’m guessing you are more than alright.”

Caspar wrenched his weapon from the dead Adrestrian, and Sylvain couldn’t help but think that judging by the way he staggered and how his other arm bent stiffly at his side, he was the one who was _not_ all right.

The dust had cleared and Sylvain’s vision had cleared as well. The ground still smoldered where the lightning struck, and his horse had ran quite a distance away. But now he could see the mages. And the archers, and the other half a dozen axe and sword wielding soldiers closing in around them.

Ashe pulled the arrow back and let it fly. 

Thud.

One mage fell dead.

“Look at these chumps,” Caspar snarled, twirling his giant axe and taking a warning step forward. “Who’s first?”

“Hey, now,” Ashe began, voice stricken with concern. “Take it easy, Caspar. You’re hurt. You should stay back and wait for help.” 

Caspar merely scoffed, ignoring the worried look of his comrade, and dug his feet into the ground as the first wave of enemies leapt towards them. The Imperial defector easily dodged the first thrust of a lance and viciously spun around, one-handedly swinging that giant axe into the skull of the fool unfortunate enough to miss. Blood splattered across his arm and flecked his cheeks, and there was an unnerving enjoyment in his smile.

“And let you guys have all the fun? Nah, like hell I’m doing that!”

Sylvain raised his lance just in time to block the blunt of a sword. With shaking arms, the blade and shaft pushed against each until Sylvain twisted his weapon and wrenched the sword from the foe’s grasp. He kicked the baffled swordswoman savagely in the stomach, and what could only be Ashe’s arrow pierced her chest immediately after. She retched in pain and fell to the ground, and he spiked the tip of his lance through her back before narrowly dodging a raging magical flame.

An arrow volleyed into the thigh of the mage, and Sylvain took this advantage to ruthlessly end her life.

To Sylvain’s left, he spotted Caspar rushing towards two other enemies. His axe spliced through the air and through the neck of the nearest one. Caution tossed to the winds, he revolved around as the remaining soldier surged, face white in terror, and a lance sliced a gash in Caspar’s cheek. His eyes flashed a mix of amusement and fury, and, in an instant, his knee slammed into the other’s stomach. The man crumbled and was mercilessly impaled. Caspar breathed out raggedly—and did he just chuckle? —and then charged towards another target.

Two more arrows burrowed holes in men’s hearts and the Lance of Ruin cleaved through another sorcerer.

Inches from his next victim, an arrow bounced off Caspar’s armored chest and another sunk between the gaps in his right metal-plated boot. He grunted in more surprise than pain and stumbled. His aim was hindered and his tomahawk only grazed his foe. 

Sylvain’s weapon claimed the life of the first archer who attacked, and he pivoted around in search of the other.

Stubbornly—foolishly—Caspar pushed forward as the Imperialist swung his sword, moving right into the path of the blade.

An arrow struck her in the chest and she slumped backwards. Another followed, and speared into her forehead. 

Ashe sighed in exasperation. “Leave this to Sylvain and me. You need to take it easy.” He fired again, this time into an enemy closing in on Sylvain. It missed the vitals but Sylvain finished the job easily.

“Hell no! I’m fine!” He pulled at the arrow lodged in his leg, and grimaced ferociously.

Ashe spun around and his next shot fell a soldier sneaking up behind his stubborn friend. “You haven’t been thinking right since we ran into Count Bergliez. You’re going to—”

“Are you trying to say I’m scared or something?” Caspar gave up yanking out the arrow, his attention now fully on the archer.

“I wasn’t, but when Lonato—“

“Do you have to do this now?” Sylvain interrupted, parrying an axe with his lance. “Save it! I'm trying to make it out of here alive! Preferably in one piece. Can't say the same about the two of you.”

Another draw of the bow. “I’m just worried about—“

“Shut the hell up!” spat Caspar. Ashe fell silent, but his glare held a tinge of pity.

Sylvain buried the skeleton relic in the chest of another Adrestrian. “Enough!”

Caspar spat blood out in defiance and hissed loudly as he snapped the arrow’s shaft, leaving the tip still embedded in his leg. He stumbled back with gritted teeth, and his gaze caught Sylvain’s for a moment. The way he instantly averted his eyes seemed to be a silent acknowledgement that he would cooperate. 

Suddenly his eyes widened on something in the distance and the “Oh, shit” that slipped from his lips alerted Sylvain to reel around to investigate himself.

What he saw made his breath catch in his throat and his stomach lurch.

Off in the distance Mercedes stood a mere meter before an ominous familiar figure, face hidden in a skeleton mask and a tattered cloak blowing ghostly in the rising wind—the Death Knight. Her staff was discarded on the ground and although he could make out the towering form of Dimitri plowing through a circle of Imperialists toward her, he knew His Highness could not make it to her in time.

Instantly, Sylvain revolved around in search of his steed. Once spotted not far off, he dashed toward it without a thought of his own safety. Several enemies took the opportunity to advance and Ashe’s worried protests punctured the air, but Sylvain paid them no head. An arrow found the neck of an Adrestrian who dared to interfere, and he heard Caspar’s crazed roar in his shadow.

He sprang onto the stallion’s back, snapped up the reigns, and spurred his heels into the horse’s flank. The beast leapt forward and began a steady pace. 

Yet it wasn’t fast enough.

He squeezed its flank tighter and bellowed a command. The beast sped up, but it still wasn’t fast enough.

Rain started to drip in a steady rhythm from the dark sky. The droplets sunk between the strands of his hair and puttered off Sylvain’s armor with percussional tings. The horse neighed, but he urged it onward. Their pace was all ready slowed by littered corpses and scattered burning fires he would not let rain reduce it any further. 

Mercedes was just so far away.

He watched her swing her arms vulnerably wide open and plead, “Emile, you don’t have to do this. Come with me. We can go home together.” 

The forlorn figure hesitated for a moment before replying. “Leave,” he hissed, motioning her away with his hand. “The place of your death is not here.”

Sylvain clicked his tongue and pressed his legs tighter still against his horse. He needed to go faster. She was still so far away. 

“No! Emile!” Tears choked her voiceas she took a brave step forward. “Come with me. It’s not too late to be family.”

The Death Knight raised his scythe and Mercedes halted. “I told you I would not spare you next we met.”

Sylvain’s crest burst forth and its radiating glow encircled him. He hoisted The Lance of Ruin high above his head and let it fly with desperate ferocity, hoping with all his might that it would strike his target dead.

The weapon sliced through the air, humming sinisterly as it drew closer and closer.

Sylvain’s breath caught in his throat and his heart beat in time with the gallop.

The Death Knight turned his head and shifted.

A thunderous boom of ancient power shook through the fort and bone upon metal screeched in accompaniment as the Lance of Ruin pierced through the skeleton’s breastplate.

He stumbled backwards, but to Sylvain’s horror, yanked the relic out of chest with little concern. He tossed it to the ground, where it clattered and the orb in the middle dimmed.

“Mercedes!” Sylvain roared, despairingly. He continued to push forward, unconcerned that he was now unarmed. If he could just reach her he could protect her. Be a shield. Push her to the side. Adrenaline propelled him forward without a plan, and foolishly he wasn’t paying attention to anything besides Mercedes and her long lost brother.

His horse wailed a painful cry, and suddenly Sylvain fell. He impacted with the ground in a split second, world spinning as dirt blurred his sight and pain ripped across his temple. His steed crashed down with him, and its weight crushed his leg still trapped in the stirrups. It whined solemnly and became still.

He could barely see her now with his collapsed steed blocking his view. He tried to move but found himself frustratingly pinned. Blood and rain dripped down his face, slipping over his mouth as he struggled for each haggard breath. He grunted and struggled, but could not push the beast off.

The Death’s Knight focus returned to Mercedes. She was going to die and he was going to watch. The only woman who ever truly mattered, who understood his pain and accepted him. 

He promised to protect her, didn’t he? Like always he broke promises.

A clap of thunder shook the fort and a lightning bolt struck down upon the Death Knight. Another followed quickly after.

“Don’t you dare hurt Mercie!” Annette practically choked. Her black horse trotted to the side of Sylvain, and he could only raise his body enough to see her small feet within the stirrups.

The Death Knight collapsed and lay motionless. Mercedes’ face broke in an instant, and she gasped on the onslaught of tears. She dropped to her knees and lifted the mask off of the haunting warrior, revealing golden locks of hair identical to hers. She placed his head in her lap and sobbed.

A complex mix of relief and sympathy swept over Sylvain as the world around him spun and shifted and grew dim. He vaguely noticed Dimitri effortlessly lift the deceased horse off his body and Annette’s strained voice beg a resisting Mercedes to come with her.

* * *

Something shook the cot and an assortment of unknown objects clattered across the stone floors. Sylvain awoke with a gasp and a cold sweat. The nausea boiled in his stomach and vibrations rung in his ears. Yet as he breathed heavily to still his discomfort, the smell of lavender soothed him. He clutched the shawl still draped over his chest and stared at it drowsily. Slowly his heart beat eased.

She was safe; he remembered.

Glass crashed on hard ground and he bolted up with a grimace to find Annette at the edge of his bed, knelt over and crowding an assortment of medical supplies haphazardly into her arms.

Levity returning to him as he sunk back into his pillow. He spoke up, “Your sulking face still is pretty cute.” Falling into old habits was easy.

Startled blue eyes found his and he expected her to puff up in annoyance, but instead tears threatened her eyes. She averted her gaze back to the objects on the floor, continuing to gather them.

“I don’t have time for your teasing right now,” she replied curtly.

“I just don’t want a face as cute as yours to be spoiled by a frown.”

She stopped right before her fingers wrapped around a roll of bandages and glared at him. “Everyone is working hard, and they really need these supplies.” Her breath hitched and her voice fell to a mumble. “And, of course, I ruin everything.”

“Lighten up. It’s not a big deal.” He began to rise but pain abruptly stopped him. “Normally, I’d offer to help you out, but it seems I’m the one who really messed up.” He offered a dry painful laugh.

She doesn’t join him in laughter. Instead, her hands shook and she clutched the items closer. “I made the worst—the most horrible mistake ever.” A tear spilled from the corner of an eye and her voice cracked at every word. “Mercie...she’s suffering so much. And it’s all my fault. Her brother—I—I—”

She broke into a shivering sob and Sylvain looked away. He remained silent a long time. At last he spoke, “It’s my fault, Annette. If I had kept my promise, you wouldn’t have had to do it.”

Sylvain only knew how to break hearts. Of course, he wouldn’t know how to shield the heart that really mattered. 

  
  



End file.
